Crystallization and melting behavior of polypropylene (PP) in (vulcanized nanoscale polybutadiene rubber powder/PP) polymer-nanocomposites

Radiation vulcanized polybutadiene rubber powder (PBRP) was prepared and blended with polypropylene (PP). Melting behavior and isothermal crystallization kinetics of PP and prepared polymer-nanocomposites were investigated by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). It was found that the addition of PBRP increased the melting (T-m) and crystallization (T-c) temperatures, as well as the crystallization rate of PP. By study on isothermal crystallization kinetics of PP, in terms of the Avrami equation, the Avrami exponent n for the pure PP was determined about 2. Using and increasing the amount of PBRP in the nanocomposites increased the n value up to 3.4; indicating a heterogeneous nucleation followed by a three-dimensional crystal growth. WAXS results showed that the existence of PBRP had no effect on the a-form of PP crystals. However, the use of PBRP promoted the crystals to become perfect and resulted in a larger crystallite size. (C) 2015 Elsevier B.V. All rights reserved.